The use of resist-type materials for color filters in the production of image sensors, such as Charged Coupled Device (CCD) image sensors and Complimentary Metal Oxide Semiconductor (CMOS) image sensors, raises contamination concerns. For instance, volatile components in the resists may cause substantial out-gassing during exposure to radiation, e.g. during exposure to radiation in a lithographic image sensor manufacturing process. The out-gassing may lead to contamination and damage of the projection lens or the surrounding area, which in turn may require increased maintenance to clean the lens or even replacement of the lens or surrounding parts. Objectives of the present invention include providing methods and apparatus addressing out-gassing concerns.
Lithography systems employing gas purgehoods are mentioned in EP 1098226 and U.S. 2004-0212791.